Temperature control system for freezers

ABSTRACT

A temperature control system for freezer mechanism of the continuous freezing type and in which various combinations of ingredients are fed into a freezing chamber and frozen. A scraper slowly rotates over the inner surface of the chamber to remove the frozen mix from the surface of the cylinder. The freezing chamber is pressurized and the product forced out of a serving valve at one end of the freezer and the temperature of the product is sensed and is used to control the refrigeration means. A heat anticipator is also energized during the draw and heats the sensing means so that the need for refrigeration is anticipated prior to the time it is actually required, thereby eliminating any time lag in supplying refrigeration.

United States Patent Werner [75] Inventor: Bernfried M. Werner, PompanoBeach, Fla.

[73] Assignee: Louis A. M. Phelan, Pompano Beach, Fla.

[22] Filed: March 25, 1971 [21] Appl. No.: 127,886

[52] US. Cl. ..62/135, 62/180, 62/202, 62/392 [51] Int. Cl. ..F25c 7/10[58] Field of Search ..62/l35, 180, 392, 202; 236/68 B [56] ReferencesCited UNITED STATES PATENTS 2,930,203 3/1960 Koch ..62/l35 3,183,6815/1965 Lutz et al ..62/342 X j 0 Coy/val Feb. 13, 1973 ABSTRACT Atemperature control system for freezer mechanism of the continuousfreezing type and in which various combinations of ingredients are fedinto a freezing chamber and frozen. A scraper slowly rotates over theinner surface of the chamber to remove the frozen mix from the surfaceof the cylinder. The freezing chamber is pressurized and the productforced out of a serving valve at one end of the freezer and thetemperature of theproduct is sensed and is used to control therefrigeration means. A heat anticipator is also energized during thedraw and heats the sensing means so that the need for refrigeration isanticipated prior to the time it is actually required, therebyeliminating any time lag in supplying refrigeration.

2 Claims, 5 Drawing Figures PATENTEDFEB 13 I975 3,715,893 SHEET 10F 3 lK K i x u INVENTORI w .5. M h zz/vu ATTORNEY PATENTEUFEB 13 I975 SHEET 2OF 3 INVENTOR.

19. M h zz/vm BY:

PATENTEUFEB 13 1973 SHEET 3 BF 3 INVENTOR.

5. M l/zz/vzl BY.

TEMPERATURE CONTROL SYSTEM FOR FREEZERS BACKGROUND OF THE INVENTION that'prior art device, a beater was used for forcibly ejecting the productone end of the freezing cylinder and also acted to aerate the product,that is to beat the required amount of air into the product to providewhat is known as over run. That beater rotated at such a speed to createundesirable heat within the freezing chamber.

SUMMARY OF THE INVENTION The present invention provides a temperaturecontrol system for a continuous freezer in which the product isdischarged from the cylinder due to the fact that the cylinder ispressurized. More specifically, the freezer includes a pump forfurnishing a product mix under pressure to the freezing chamber andmaintains the freezing chamber sufficiently pressurized so that theproduct is discharged from the freezer by pressure whenever the draw-offvalve is open. This pump is operated by a pressure switch located in thefreezing cylinder. A rotatably scraper is coupled electrically to therefrigerant means to simultaneously slowly move over the surface of thecylinder and remove the mix from the cooled surface. The presentinvention provides a temperature control system for such a freezer,which system has a temperature sensing element located in the criticalarea of the freezer adjacent the draw-off valve, and also includes aheater for the sensor which serves to anticipate refrigerationrequirements and heat the sensor during each draw so that refrigerationcommences prior to the time it would otherwise be called for by thesensor alone. The arrangement is such that the sensor is also beingheated by the heater while the refrigerant is being supplied, andconsequently, when the freezer is operative and a large amount ofproduct is being drawn off, the refrigeration will not shut off when acolder batch of product that was located in the center of the freezer,passes over the heat sensor at the discharge end of the cylinder.

The control system also includes an actuator rod that is actuated bymovement of the draw off valve, and which rod, through suitableswitches, causes actuation of the motor for the rotatable scraper in thecylinder and also causes actuation of the temperature control.

The present invention provides a control system in which the rotatablescraper in the freezer can also run independently and regardless ofwhether the refrigerant compressor is on, so as to be able to clean outthe freezer when the refrigeration is not desired. In the device of thepresent invention, the scraper could be inoperative and it would stillbe possible to get the product out of the freezer because of thepressurization thereof.

With the control system above mentioned, the freezer after a stand-bycondition for a period of time may have the product temperature in theentry and discharge ends of the freezer different than the temperaturein the center of the freezer. Then, if a considerable amount of productis drawn out of the cylinder, the control system prevents an undesirableshut-off of the refrigerant compressor in the event the colder productin the center of the freezer moves over the sensor element located inthe discharge end of the freezer.

These and other objects and advantages of the present invention willappear hereinafter as this disclosure progresses, reference being had tothe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal, partialcross sectional view through a continuous freezer embodying the presentinvention;

FIG. 2 is an enlarged, fragmentary cross sectional view of a portion ofthe device shown in FIG. 1',

FIG. 3 is a plan view of the device shown in FIG. 2;

FIG. 4 is a front view of the device shown in FIG. 2 and also showingthe pump automatic switch and scraper refrigeration automatic switch;and

FIG. 5 is an electrical circuit diagram used with the present invention.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring in greater detail toFIG..1, the continuous freezer includes a freezing cylinder C, a freshmix tank T containing mix M, a pump P mounted in the tank T for mixingair and mix M together and forcing it into the freezing cylinder viaopening 2. The freezing cylinder also includes a rotary scraper assembly3 and a draw'off valve V at the front end of the freezer. The cylinderfurthermore includes an annular freezer chamber 4 located forsubstantially the full length of the cylinder C.

If a more complete description of the pump P is believed to be eithernecessary or desirable, reference may be had to the US. application,Ser. No. 59,191, filed July 29, 1970 and entitled Positive Displacement,Gear Type Pump.

If a more complete description of the draw off valve is believed to beeither necessary or desirable,

reference may be had to the US. application, Ser. No.

59,100, filed July 29, 1970 and entitled Freezer Door and Draw Off Valvefor a Continuous Freezer.

If a more complete description of the scraper assembly 3 is believed tobe either necessary or desirable, reference may be had to the US.application, Ser. No. 59,099, filed July 29, 1970 and entitled ScraperAssembly and Material Retarder for a Cylindrical Continuous Freezer.

For purposes of the present invention, it is believed sufficient to saythat the freezing cylinder receives the mix via opening 2, and therotating scraper assembly keeps the product from freezing on thecylinder wall. The interior of the cylinder is pressurized by the pump Pso that the product is forcefully ejected through the outlet 5 at thedraw off end of the freezing cylinder when the plunger 6 of the valve israised. If excessive pressure is present in the cylinder when the drawoff valve is open, the product is ejected too rapidly. Furthermore, itis dangerous for excessive pressure to A pressure control switchassembly SA is mounted in I the rear wall 7 of the freezing cylinder andhas a head 10 which is located within the cylinder and is exposeddirectly to the product therein. The switch assembly includes a threadedportion 11 which extends through the wall 7 and has a nut 12 threadablyengaged on portion 11 and by means of which the head 10 can be drawn uptightly against the interior of the wall 7. In this manner, the switchassembly is rigidly mounted to the rear wall. If a more completedescription of the switch assembly SA is deemed to be either necessaryor desirable, reference may be had to the US application, Ser. No.59,192 filed July 29, i970 and entitled Pressure Sensitive SwitchAssembly. Reference will also be made later to the function andoperation of the switch assembly SA in connection with the circuit shownin FIG. 5 of the present invention.

The sensor and heater 36 located at the discharge, lower end of thefreezing cylinder will now be described.

The sensor 20 includes a conventional thermobulb which is located inheat conductive tube 22, which tube in turn is located in a groove 24(FIG. 1) that is formed in the periphery of the lower discharge end ofthe freezer cylinder wall. This tube 22 is soldered or otherwise fixedin intimate contact to the cylinder and thus in good heat transferringrelationship therewith. The tube 22 is closed at its end 26 while itsupper end 28 extends upwardly over the freezing cylinder and terminatesin a control box 30 located above the cylinder. The sensor 20 includes atube 32 which extends through tube 22 and terminates in box 30. Sensor20 and tube 32 contain a thermal expansive fluid which provides acontrolled expansion and contraction of a bellows 34, or the like foractuating a spring loaded switch 98 as shown in FIG. 5. Also locatedwithin the tube 22 and lying along side the thermobulb of the sensor 20,is a heater 36 in the form of a high resistance wire that also extendsupwardly through the tube 22 and is connected to the secondary of thetransformer 40. It will be noted that the heater 36 simply liesalongside the thermobulb and can be easily removed from the tube withoutremoval of the bulb. The thermobulb of sensor 20 acts to sense thetemperature of the product that is located in the critical area of thecylinder just inside the draw off valve. Ordinarily, the sensor, when itis warmed sufficiently by the product, would call for the refrigerationto commence. The purpose of the heater 36 is to heat the sensor 20 andthus cause actuation of the refrigeration means, even though the productin the critical area is not cold enough to do so. In other words, theheater anticipates freezing requirements of the freezer, as will morefully appear.

Also connected in the temperature control circuit shown in FIG. 5, is adouble pole, double throw switch 50, which as shown in FIG. 4, islocated on the front of the machine within easy reach of the operator.The toggle switch 50 can be moved to either a scraper operating positionor an automatic refrigerant position as will appear. Also located in thecircuit is a double pole, single throw toggle switch 60, which as shownin FIG. 4, is also within easy reach of the operator standing at thefront end of the machine. This automatic pump switch 60 can be movedbetween an off position and an automatic pump position, as will appear.

The freezer has a rotatable scraper 3 mounted within it, as fullydescribed in the said U.S. application Ser. No. 59,099 and this scraperis slowly driven from the rear end of its shaft 62a by the scraper motor63 (FIG. 5).

Referring to FIGS. 2, 3 and 4 in particular, a plunger is slideablymounted in a tube 71 in the front of the machine and its outer end abutsagainst the draw off valve handle. A vertically extending post 72 isrigidly attached to the rear end of plunger 70 and extends upwardlytherefrom. A leaf spring 73 is fastened at one end by a screw 74 to theframe of the machine and acts to bias the plunger 70 outwardly to aposition in which it abuts against the draw off valve handle. When thedraw off valve handle is swung outwardly away from the machine to drawproduct from the serving valve, the post 72 contacts the plungers ofmicro-switches 75 and 76. Micro-switch 75 closes when the draw off valveis open and provides electrical power to the transformer 40, thusheating the sensor 20 regardless of whether refrigerant is beingsupplied. Micro-switch 76 is also closed when the draw off handle ismoved to dispense the product, and this micro-switch 76 then actuatesthe motor 63 of the rotary scraper 3.

Referring particularly to FIG. 5, a schematic circuit is showninterconnecting the various controls for the mix pump motor 58, thescraper motor 63, and the compressor motor 64 including a pressurecontrol switch 65 of switch assembly SA. In FIG. 5, the several motorsand controls are interconnected to a common set of power lines 80 and 81with line 80 shown as the positive or hot side and line 81 forming acommon or neutral return. In an actual construction, separate powersupplies may be provided for the operation of the motors and for theinter-related control circuitry, as presently described. The compressormotor 64 is connected to the power lines through a compressor starter CSincluding a winding 82 for selectively closing associated contacts tocomplete the circuit. The scraper motor 63 is similarly connected to thepower lines 80 and 81 by a scraper starter SS having a control winding83 which, upon energization, completes the circuit to the scraper motor63. The mix pump motor 58 is directly powered from the power lines 81-82through the toggle switch 60. In the illustrated embodiment of theinvention, the toggle switch 60 is shown as a double pole, single throwunit having a pair of contacts 84 connected in common to each other andto the power line 80. The toggle switch further includes a pair ofmovable contact poles 85 and 86 which are ganged and interconnected tothe toggle switch 60 for simultaneous positioning between the offposition and the automatic drive position in engagement with thecontacts 84. The

contact arm 85 is connected via a lead 87 to the one side of the shellpressure switch 65, the opposite side of which is connected to the oneside of the mix pump motor 58. The opposite side of the mix pump motor58 is connected directly to the neutral or return line 81. Thus, withthe switch 60 in the automatic or closed position, power is directlyconnected across the mix pump motor 58 in series with the shell pressureswitch 65. The motor will operate until the pressure switch 65 opensindicating the desired transfer of material under the desired pressureto the transfer or freezing cylinder C. The opposite side of the switch60 and in particular, contact arm 86 is connnected directly in serieswith the heater control switch 75 to the one side of the primary winding88 of the heater transformer 40, the opposite side of which primary isconnected directly to the neutral or common return line 81. The switch75 is normally open, thus closure of the switch 60 does not providepower to the transformer 40. However, whenever the draw handle H isactuated to open the discharge valve V, the switch 75 will close andprovide power to the transformer primary 88. The transformer is astepdown transformer and with the secondary 89 connected directly acrossthe heater 36. For example, the transformer may reduce the incomingvoltage to a lower voltage to provide the desired heating current to theheater 36 which in turn will provide the desired anticipatory heating ofthe sensor 20. The heating effect will be maintained as long as valve Vis open. The heater switch 75 which is controlled by the valve isinterlocked through the draw switch 76 to the operation of thecompressor motor 64 and the scraper motor 63. Thus, the draw switch 76and the temperature control 34 is interconnected into the circuitthrough the toggle switch 50. The illustrated toggle switch is shown asa double pole three position or double throw switch having a pair ofcontact arms 90 and 91 ganged to each other and to the common toggle 50for simultaneous positioning between the illustrated off position,scraper operating position, and the automatic position. The contact arms90 and 91 are connected in common to the power line 80 and thus both arehot contacts for selectively supplying power to the various portions ofthe circuit as follows. In the off" position, the contacts remove powerfrom the several related contacts. In the scraper position, the contactarm 90 engages the dead contact, while the contact arm 91 engages acontact 92 which is connected via a lead 93 directly to the one side ofthe coil 83 of the scraper starter SC. The opposite side of the coil 83is connected directly to the neutral or return line. Thus with thetoggle 50 moved to the scraper position, power is directly applied tothe scraper starter winding 83 which will close its contacts and providepower to the scraper motors 63 to permit the previously describedindependent operation of the scraper. In the alternate or automaticposition of the toggle switch 50, the contact arms 90 and 91,respectively engage contacts 94 and 95 to supply power thereto. Thecontact 94 is connected via a lead 96 to the one side of the draw switch76. The draw switch 76 is a normally open switch coupled in common withthe heater switch 75 to the draw handle H. Thus the circuit from thecontact via the lead 96 is normally held open at the draw switch. Whenthe handle is rotated to open the valve, the draw switch 76 willsimultaneously close with the heater switch and transfer powertherethrough to a line 97. The line 97 is connected to the scrapercontact 92 and thus directly to the line 93 which in turn provides powerto the coil 83 of the scraper starter SS. This thus provides power tooperate the scraper motor 63 whenever the valve V has been opened towithdraw mix from the freezer cylinder C.

The alternate contact of the toggle switch 50 interconnects thetemperature control into the circuit and in particular, the temperaturecontrol switch 98 which is controlled by the expansion and contractionof the fluid within the sensor bulb 20. Thus, the contact 95 isconnected via a lead 99 to the one side of the switch 98, the oppositeside of which is connected via a lead 100 to the winding 82 of thecompressor starter CS. The opposite side of the winding 82 is connecteddirectly to the neutral line 81. Thus the winding 82 of the compressorstarter CS is connected into the circuit through the automatic positionof the toggle switch 50 in series with the temperature control contactsor switch 98, of the temperature control 34. The compressor motor 64will therefore be driven whenever the temperature sensor or controllercloses the switch 98 to provide the desired power to the compressorstarter CS and only until such a time as the sensor indicates that themix is below the desired discharge temperature. The sensing is of coursemodified by the heating provided by the high resistance wire 36 duringthe discharge.

In addition, a lead 101 interconnects the winding 83 of the scraperstarter to the hot side of the compressor motor 64. Consequently,whenever the compressor starter CS is actuated to energize the motor 64,it will also energize the scraper starter SS and provide for thesimultaneous rotation of the scraper motor 63. This will insure theremoval of the material adjacent the surface any time the cylinder isbeing cooled to lower the temperature of the mix within the cylinder C.i

The scraper 3 is in effect a slave to the refrigerant compressor, thatis to say, when the compressor goes on, the scraper goes onautomatically. However, the scraper 3 can also rotate independently fora cleaning out operation when it is not desired to continuerefrigeration. Furthermore, the scraper could be inoperative and itwould still be possible to remove the product from the cylinder becauseof the pressurization thereof.

The operation of the unit is as follows.

Assuming that the machine is tight, that is the serving valve V isclosed, and the door and pump assembly sealed. The product mix would bepoured into the tank T and the pump switch 60 turned on to the automaticposition. When the pump P stops running, the pressure in the cylinder Chas risen to the operating pressure. Then the other toggle switch 50 onthe front of the machine would be moved to the automatic refrigerationposition which starts the freezing cycle with a supply of cooling to thecylinder C and which also turns the scraper 3 on. The machine is then onthe automatic position, after which 15 to 20 minutes are required tolower the cylinder temperature and the mix within the cylinder to theproper operating temperature at which time switch 98 opens to shut downthe compressor motor 64 and the scraper motor 63.

if, thereafter, the cylinder temperature adjacent the discharge enddecreases, the switch 98 again closes and recycles the motors to againraise the mix to the desired temperature.

The operation of the draw off valve V is as follows. Assume the operatorwishes to make a draw and he opens the draw off valve. This permits theplunger 70 to extend outwardly under the force of spring 73, therebyclosing the two micro-switches 74 and 75. The microswitches respectivelyenergize the scraper motor 63 and simultaneously provides power via thetransformer 40 to the heater 36. if the heater 36 is on for asufficiently long period of time, that is if more than one productserving is made for example, then the heater 36 acts to heat the sensorthermobulb sufficiently to actuate the switch 98 and turn on therefrigerating compressor motor 64 through closure of starter CS. If theproduct temperature is still at the desired degree of coldness, theheater element 36 cools off rapidly after the draw off valve V is closedand thereby turns the scraper motor 63 and compressor motor 64 off.

Referring again to the pressure switch assembly SA, its switch 65 isclosed when the pressure in the cylinder C has dropped below theoperating pressure and to a selected level. The pressure pump P againraises the pressure level to a selected maximum operating level, theswitch 65 opens, and stops motor 58. The pressure switch 65 and pump Pare independent of the control system as long as the pump switch 60 ison the pump automatic position.

With the present invention, the sensor 20 is also being heated eventhough refrigerant is being supplied. This has the advantage of insuringthat when the unit is running and a considerable amount of product isbeing drawn, the refrigerant compressor will not turn off in the event acolder batch of the product located in the center of the cylinderhappens to move to the front of the cylinder, thereby cooling down thesensor 20. With the present control system, the refrigerant compressormotor 64 will not shut off because the sensor is being heated.

In order to clean the machine after a days operation for example, thetoggle switch 60 would be moved to the off position and the toggleswitch 50 would be moved to the scraper position, thereby permittingdraw off of all of the remaining product from the cylinder C.

I claim:

1. In a freezer apparatus including a freezer cylinder adapted todischarge finished products out of one end and having a manuallyoperated valve means including a pivoted handle, a mix tank associatedwith said freezing cylinder, a mix pump adapted to transfer the mix fromthe tank to the freezing cylinder and simultaneously mixing airtherewith to form an aerated mix, a scraper rotatably mounted withinsaid freezing cylinder and revolvable about the inner surface to scrapethe mix from the surface of the freezing cylinder, a refrigerant meansassociated with said freezing cylinder for reducing the temperature ofthe aerated mix to a preselected temperature, a temperature sensingelement mounted adjacent the discharge end of the freezing cylinder andproviding a signal proportional to the temperature of the dischargingfrozen mix, a preheater associated with said sensing means, and circuitmeans connected to actuate said mix pump, said scraper said refrigerantsupplying means and said heater, sai C11- cuit means including a pair ofdraw related actuated switches including a heater switch and a drawswitch, a switch operator coupled to said pivoted handle tosimultaneously close and open said switches, a manually operable on-offswitch for simultaneously providing power to the mix pump and to saidheater switch; said circuit including a pressure switch mounted in thefreezing cylinder and connected in the circuit to the mix pump tomaintain operation of the mix pump until a predetermined mix pressure isestablished within the freezing cylinder, said circuit including afreezing cylinder control switch including a first position to directlydrive the scraper and a second position providing power to thetemperature control sensing means and to the draw switch, saidtemperature control sensing means being connected to simultaneouslyenergize said refrigerant supplying means and said scraper, and saiddraw switch being connected to directly actuate said scraper.

2. The freezer apparatus of claim 1 wherein said switch operatorincludes a rod member slideably mounted with one end engaging saidhandle, a spring means urging said rod member toward said handle, saidrod member having a laterally extended element, and said draw relatedswitches are mounted in stacked relation with aligned input elements inthe path of said extended element for actuation in response to movementof said handle to a withdrawn position. 4

1. In a freezer apparatus including a freezer cylinder adapted todischarge finished products out of one end and having a manuallyoperated valve means including a pivotEd handle, a mix tank associatedwith said freezing cylinder, a mix pump adapted to transfer the mix fromthe tank to the freezing cylinder and simultaneously mixing airtherewith to form an aerated mix, a scraper rotatably mounted withinsaid freezing cylinder and revolvable about the inner surface to scrapethe mix from the surface of the freezing cylinder, a refrigerant meansassociated with said freezing cylinder for reducing the temperature ofthe aerated mix to a preselected temperature, a temperature sensingelement mounted adjacent the discharge end of the freezing cylinder andproviding a signal proportional to the temperature of the dischargingfrozen mix, a preheater associated with said sensing means, and circuitmeans connected to actuate said mix pump, said scraper, said refrigerantsupplying means and said heater, said circuit means including a pair ofdraw related actuated switches including a heater switch and a drawswitch, a switch operator coupled to said pivoted handle tosimultaneously close and open said switches, a manually operable on-offswitch for simultaneously providing power to the mix pump and to saidheater switch; said circuit including a pressure switch mounted in thefreezing cylinder and connected in the circuit to the mix pump tomaintain operation of the mix pump until a predetermined mix pressure isestablished within the freezing cylinder, said circuit including afreezing cylinder control switch including a first position to directlydrive the scraper and a second position providing power to thetemperature control sensing means and to the draw switch, saidtemperature control sensing means being connected to simultaneouslyenergize said refrigerant supplying means and said scraper, and saiddraw switch being connected to directly actuate said scraper.
 1. In afreezer apparatus including a freezer cylinder adapted to dischargefinished products out of one end and having a manually operated valvemeans including a pivotEd handle, a mix tank associated with saidfreezing cylinder, a mix pump adapted to transfer the mix from the tankto the freezing cylinder and simultaneously mixing air therewith to forman aerated mix, a scraper rotatably mounted within said freezingcylinder and revolvable about the inner surface to scrape the mix fromthe surface of the freezing cylinder, a refrigerant means associatedwith said freezing cylinder for reducing the temperature of the aeratedmix to a preselected temperature, a temperature sensing element mountedadjacent the discharge end of the freezing cylinder and providing asignal proportional to the temperature of the discharging frozen mix, apreheater associated with said sensing means, and circuit meansconnected to actuate said mix pump, said scraper, said refrigerantsupplying means and said heater, said circuit means including a pair ofdraw related actuated switches including a heater switch and a drawswitch, a switch operator coupled to said pivoted handle tosimultaneously close and open said switches, a manually operable on-offswitch for simultaneously providing power to the mix pump and to saidheater switch; said circuit including a pressure switch mounted in thefreezing cylinder and connected in the circuit to the mix pump tomaintain operation of the mix pump until a predetermined mix pressure isestablished within the freezing cylinder, said circuit including afreezing cylinder control switch including a first position to directlydrive the scraper and a second position providing power to thetemperature control sensing means and to the draw switch, saidtemperature control sensing means being connected to simultaneouslyenergize said refrigerant supplying means and said scraper, and saiddraw switch being connected to directly actuate said scraper.